FR3135578A1 - MONITORING THE INTERNAL TEMPERATURE MEASURED IN AN ELECTRIC MOTOR MACHINE OF A VEHICLE - Google Patents

Abstract

A monitoring method is implemented in a vehicle comprising an electric driving machine periodically subject to an internal temperature measurement. This method comprises a step (10-40) in which information representative of a gradient of internal temperature measurements over a first chosen time interval is periodically determined, and when this information is greater than a first chosen threshold, the use of the electric motor machine (MME). Figure 3

Description

MONITORING THE INTERNAL TEMPERATURE MEASURED IN AN ELECTRIC MOTOR MACHINE OF A VEHICLE Technical field of the invention

The invention relates to vehicles comprising an electric driving machine forming part of a powertrain, and more specifically the monitoring within such vehicles of measurements of the internal temperature in this electric driving machine.

State of the art

Certain vehicles, possibly of the automobile type, include a powertrain (or GMP) comprising an electric driving machine supplied with electrical energy by a rechargeable main (or traction) battery during recharging phases.

Here we mean “main (or traction) battery” a battery responsible for supplying electric current, on the one hand, to an on-board network and a service battery of its vehicle via a converter, and, on the other hand, , each electric driving machine of the GMP of its vehicle.

Furthermore, the term “on-board network” is understood to mean an electrical supply network to which electrical (or electronic) equipment (or components) which consume electrical energy are coupled.

In addition, the term "service battery" means here a battery rechargeable at least by a converter of the vehicle (powered by the main battery) and responsible for supplying electrical energy to the on-board network, in addition to that supplied by the converter, and sometimes in place of this converter.

In the aforementioned vehicles, the electric driving machine is generally an electric motor comprising a rotor and a stator. When such an electric motor machine is in operation, for example to provide torque to the wheels of a train of its vehicle, its stator consumes electrical energy from the main battery to create a magnetic field intended to rotate the rotor. Consequently, in operation the stator rises in temperature, and for it to operate correctly, without risk of degradation, its temperature must remain below a chosen threshold, for example of the order of 185°C.

The internal temperature of the electric motor machine, and more precisely of the stator, is therefore monitored by periodic comparison with the chosen threshold of its measurements (performed periodically by at least one internal sensor). Thus, when the internal temperature measurement becomes greater than the chosen threshold, preferably for a duration greater than a chosen time interval, the use of the electric motor machine is temporarily prohibited, in order to avoid degradation of the electric motor machine. , or even trigger a fire, and thus protect the vehicle and its passengers.

The computer which makes the aforementioned comparisons therefore makes decisions based on the internal temperature information of the electric motor machine which it receives periodically. If this computer receives an internal temperature measurement which does not correspond precisely to the actual internal temperature of the electric motor, there is a risk that it will make a decision that is unsuitable for the real situation. Indeed, if the internal temperature measurement received is strictly lower than the actual internal temperature but the latter is higher than the chosen threshold, the computer continues to authorize the use of the electric motor, even though this is potentially dangerous. . Likewise, if the internal temperature measurement received is strictly higher than the actual internal temperature and the latter is lower than the chosen threshold, the computer prohibits the use of the electric motor machine, even though this is not useful.

Furthermore, it may happen that the internal temperature measurement is substantially identical to the actual internal temperature of the electric drive machine and strictly lower than the chosen threshold, but that continued use of the electric drive machine is potentially dangerous. This is for example the case when the internal temperature of the stator rises too quickly (a situation known as “thermal runaway”).

Currently, there is no known solution for determining whether the internal temperature sensor is malfunctioning (inconsistent successive measurements) or whether there is a thermal runaway before the internal temperature becomes higher than the chosen threshold. Consequently, the invention aims in particular to improve the situation.

Presentation of the invention

To this end, it proposes in particular a monitoring method intended to be implemented in a vehicle comprising an electric motor machine periodically subject to a measurement of an internal temperature.

This monitoring method is characterized by the fact that it comprises a step in which information is periodically determined which is representative of a gradient of internal temperature measurements over a first chosen time interval, and when this information is greater than a first threshold chosen, the use of the electric motor machine is temporarily prohibited.

Thanks to the invention, it is now possible to detect a phenomenon of thermal runaway and/or a malfunction of the sensor when the increase in the internal temperature of the electric motor machine is too rapid over the first elapsed time interval, and act accordingly. consequently, at least by temporarily prohibiting the use of electric motors.

The monitoring method according to the invention may include other characteristics which can be taken separately or in combination, and in particular:

- in its step, the use of the electric motor machine can be temporarily prohibited when the determined information is greater than the first threshold chosen during a second time interval which is strictly greater than the first time interval;

- in this stage, the use of the electric motor machine can be temporarily prohibited when, in addition, the internal temperature measurement is greater than a second chosen threshold;

- in the presence of the last option, in its step we can temporarily prohibit the use of the electric motor machine when in addition the internal temperature measurement is greater than the second chosen threshold during a third chosen time interval;

- also in the presence of the last option, in its step we can use a second chosen threshold which is between 175°C and 195°C;

- in its stage, in the event of a temporary ban on the use of the electric driving machine, at least one complementary action can also be carried out in the vehicle which is chosen from a generation of an alert from a user of the vehicle prohibiting the use of the electric drive machine and recording at least one fault code representative of an internal temperature gradient problem in the electric drive machine;

- in its step we can re-authorize the use of the electric motor machine when the determined information becomes less than a third chosen threshold, less than or equal to the first chosen threshold, during a fourth chosen time interval.

The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a monitoring method of the type of that presented above to monitor periodic measurements of an internal temperature of an electric driving machine of a vehicle.

The invention also proposes a monitoring device intended to equip a vehicle comprising an electric motor machine periodically subject to a measurement of an internal temperature.

This monitoring device is characterized in that it comprises at least one processor and at least one memory arranged to perform the operations consisting of periodically determining information which is representative of a gradient of internal temperature measurements over a first interval of chosen time, and when this information is greater than a first chosen threshold to temporarily prohibit the use of the electric motor machine.

The invention also proposes a vehicle, possibly of the automobile type, and comprising, on the one hand, an electric driving machine periodically subject to a measurement of an internal temperature, and, on the other hand, a device for monitoring of the type presented above.

Brief description of the figures

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and the appended drawings, in which:

schematically and functionally illustrates an exemplary embodiment of a vehicle comprising a GMP, with an electric motor powered by a rechargeable main battery, and a monitoring device according to the invention,

schematically and functionally illustrates an exemplary embodiment of a management computer comprising an exemplary embodiment of a monitoring device according to the invention, and

schematically illustrates an example of an algorithm implementing a monitoring method according to the invention.

Detailed description of the invention

The invention aims in particular to propose a monitoring method, and an associated monitoring device DS, intended to allow the monitoring of periodic measurements mti of the internal temperature of an electric motor machine MME of a vehicle V.

In what follows, we consider, by way of non-limiting example, that the vehicle V is of the automobile type. This is for example a car, as illustrated in the . But the invention is not limited to this type of vehicle. It concerns any type of vehicle comprising a powertrain (or GMP) comprising an electric driving machine supplied with electrical energy by a rechargeable main (or traction) battery during recharging phases. Thus, it concerns, for example, land vehicles (utility vehicles, motorhomes, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and road machinery. caterpillar(s), for example), boats and aircraft.

Furthermore, we consider in what follows, by way of non-limiting example, that the vehicle V comprises a powertrain (or GMP) of all-electric type (and therefore whose traction is ensured exclusively by at least one electric driving machine MRS). But the GMP could be of hybrid type (thermal and electric).

We have schematically represented on the a vehicle V comprising an electric GMP transmission chain (and therefore an MME electric driving machine), an on-board network RB, a utility battery BS, a main (or traction) battery BP, a CV converter, and a device DS surveillance according to the invention.

The RB on-board network is an electrical supply network to which electrical (or electronic) equipment (or components) are coupled which consume electrical energy.

The utility battery BS is responsible for supplying electrical energy to the on-board network RB, in addition to that supplied by the CV converter powered by the main battery BP, and sometimes in place of this CV converter. For example, this BS utility battery can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least via the CV (current) converter. We consider in the following, by way of non-limiting example, that the BS utility battery is of the 12 V Lithium-ion type.

The transmission chain has a GMP which is, here, purely electric and therefore which includes, in particular, an electric driving machine MME, an AM motor shaft, and an AT transmission shaft. Here we mean “electric driving machine” an electric machine arranged so as to provide torque to move the vehicle V when it is supplied with electrical energy by the main battery BP, as well as possibly to recover torque in regenerative braking .

The operation of the GMP is supervised by a CS supervision computer.

The electric driving machine MME (here an electric motor) is coupled to the main battery BP, in order to be supplied with electrical energy, as well as possibly to supply this main battery BP with electrical energy, in particular during regenerative braking .

We consider in what follows, by way of non-limiting example, that the electric motor machine MME comprises a rotor, a stator, and at least one CT sensor responsible for periodically carrying out mti measurements of its internal temperature. For example, the (each) CT sensor periodically performs mti measurements of the internal temperature of the stator. For example, this period can be equal to 5 ms.

Furthermore, this electric motor machine MME is coupled to the motor shaft AM, to provide it with torque by rotational drive. This motor shaft AM is here coupled to a reduction gear RD which is also coupled to the transmission shaft AT, itself coupled to a first train T1 (here of wheels), preferably via a differential D1.

This first train T1 is here located in the front part PVV of the vehicle V. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V.

The MME electric driving machine is associated with a CG management computer which is responsible for managing its operation.

The CV converter is also responsible during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply the on-board network RB and the utility battery BS with converted electric current (to recharge it).

Note, as illustrated non-limitatively in the , that the CV converter can be part of a CH charger also including a recharge calculator (not illustrated) responsible, at least, for controlling the recharges of the main battery BP.

The main (or traction) battery BP can, for example, include electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, the main BP battery can be of the low voltage type (typically 450 V for illustration purposes). But it could be medium voltage or high voltage.

It should also be noted that the main battery BP is associated with a battery box BB which notably includes a battery calculator CB. This main battery BP and its battery box BB constitute a battery pack.

It will also be noted that in the example illustrated non-limitingly on the the vehicle V also includes a distribution box BD to which the utility battery BS, the CV converter and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the utility battery BS or produced by the converter CV, for powering the electrical components (or equipment) coupled to the on-board network RB depending on power requests received (in particular from the GMP CS supervision computer).

As mentioned above, the invention proposes in particular a monitoring method intended to allow the monitoring of periodic measurements mti of the internal temperature of the electric motor machine MME (from the CT sensor).

This (monitoring) method can be implemented at least partially by the monitoring device DS (illustrated at least partially in Figures 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal (or DSP (“Digital Signal Processor”)), and at least one MD memory. This DS monitoring device can therefore be produced in the form of a combination of electrical or electronic circuits or components (or “hardware”) and software modules (or “software”). For example, it can be a microcontroller.

The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the monitoring process. The processor PR1 may include integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or non-wired connections. By integrated (or printed) circuit we mean any type of device capable of performing at least one electrical or electronic operation.

In the example illustrated without limitation in Figures 1 and 2, the monitoring device DS is part of the management computer CG (associated with the electric motor machine MME). But this is not obligatory. Indeed, the DS monitoring device could include its own dedicated computer, which is then coupled to the CG management computer, or could be part of another on-board computer (for example the CS supervision computer).

As illustrated without limitation on the , the (monitoring) method, according to the invention, comprises a step 10-40 which is implemented when the vehicle V is in operation (at least with the contact established), and in particular when the electric driving machine MME is Operating.

Step 10-40 of the method comprises a sub-step 10 in which (the monitoring device DS) periodically determines information ig which is representative of a gradient of successive internal temperature measurements mti (from the sensor CT) on a first time interval it1 chosen.

In this step 10-40, when the determined information ig is less than a first chosen threshold s1, it is considered that there is no phenomenon of thermal runaway or malfunction of the CT sensor (no inconsistent successive mti measurements ) and therefore we (the monitoring device DS) returns to carry out sub-step 10. We in fact have the guarantee that the mti measurements provided are coherent and the assurance of operation of the stator under normal conditions of use.

On the other hand, in step 10-40, when the determined information ig is greater than the first threshold s1 chosen we (the monitoring device DS) temporarily prohibits the use of the electric motor machine MME in a sub-step 30. We considers in fact that there is a too rapid increase in the internal temperature of the electric motor machine MME over the first time interval it1 which has just elapsed, which is representative of a phenomenon of thermal runaway and/or of a malfunction of the CT sensor (incoherent successive mti measurements), and therefore for safety reasons the use of the MME electric motor machine is temporarily prohibited. This makes it possible to avoid damage to the MME electric driving machine, or even the outbreak of a fire, and therefore to protect the vehicle V and its passengers.

For example, the first time interval it1 can be between 50 ms and 150 ms. As an illustrative example, the first time interval it1 can be equal to 100 ms. But other values of first time interval it1 can be used. For example, the value of the first time interval it1 can be chosen during the development phase of the vehicle V.

Also for example, the first threshold s1 can be between 15°C and 25°C. As an illustrative example, the first threshold s1 can be equal to 20°C. But other values of first threshold s1 can be used. For example, the value of the first threshold s1 can be chosen during the development phase of the vehicle V.

Note that the information ig, which is determined during each first time interval it1, can be the gradient of the internal temperature measurements. In this case, we have ig = mti(t) – mti(t - it1), t being the end instant of the first time interval it1 which has just elapsed, mti(t) being the internal temperature measurement at time t and mti(t - it1) being the internal temperature measurement at time t – it1. But this is not obligatory. Indeed, the ig information could be derived from this gradient, and therefore representative of the latter.

It will be noted that once the temporary ban on the use of the electric motor machine MME has been decided in sub-step 30 of step 10-40, we (the monitoring device DS) returns to carry out sub-step 10 in order to to continue monitoring the mti measurements that the CT sensor continues to provide.

For example, and as illustrated without limitation on the , step 10-40 of the method can include a sub-step 20 in which (the monitoring device DS) compares each determined piece of information ig to the first threshold s1. In this case, as indicated above, if the determined information ig is lower than the first threshold s1 we return to carry out sub-step 10, while if the determined information ig is greater than the first chosen threshold s1 we carry out the sub-step 10. step 30.

It will be noted that in sub-step 30 of step 10-40 we (the monitoring device DS) can temporarily prohibit the use of the electric motor machine MME when the determined information ig is greater than the first threshold s1 chosen during a second time interval it2 which is strictly greater than the first time interval it1 (i.e. it2 > it1). This option makes it possible to avoid taking into account a single erroneous mti measurement or a single erroneous ig information which would cause the immediate completion of a main action (namely the prohibition of use of the MME electric motor machine).

For example, the second time interval it2 can be between 80 ms and 200 ms. As an illustrative example, the second time interval it2 can be equal to 120 ms. But other values of second time interval it2 can be used. For example, the value of the second time interval it2 can be chosen during the development phase of the vehicle V.

In order to determine the duration of a problem on the information ig, we (the monitoring device DS) can trigger in substep 30 a first time delay equal to the duration of the second time interval it2 as soon as the information ig becomes for the first time greater than the first threshold s1, and when this duration of the second time interval it2 expires (and we still have ig > s1, without interruption), we decide in substep 30 to at least temporarily prohibit the use of the MME electric driving machine.

Preferably, in sub-step 30 of step 10-40 we (the monitoring device DS) can temporarily prohibit the use of the electric motor machine MME when in addition the internal temperature measurement mti is greater than one second threshold s2 chosen. It will be understood that in this case, the ban is decided when we have at the same time the determined information ig which is greater than the first threshold s1 (ig > s1) and the internal temperature measurement mti which is greater than the second threshold s2 (mti > s2). If one of these two conditions is not met, nothing is done (no ban).

For example, the second threshold s2 can be between 175°C and 195°C. As an illustrative example, the second threshold s2 can be equal to 185°C. But other values of second threshold s2 can be used. For example, the value of the second threshold s2 can be chosen during the development phase of the vehicle V.

It will be noted that when the two aforementioned conditions are implemented, in substep 30 of step 10-40 we (the monitoring device DS) can temporarily prohibit the use of the electric motor machine MME when furthermore the internal temperature measurement mti is greater than the second threshold s2 chosen during a third time interval it3 chosen. This option makes it possible to avoid taking into account a single erroneous mti measurement which would cause the immediate completion of a main action (namely the prohibition of use of the MME electric motor machine).

For example, the third time interval it3 may be equal to the second time interval it2. This makes treatment easier. But the third time interval it3 could be different from the second time interval it2.

It will also be noted that in sub-step 30 of step 10-40, when the temporary ban on the use of the electric motor machine MME has been decided, it is also possible to carry out (the monitoring device DS can trigger the implementation ) in the vehicle V at (at) least one complementary action which is chosen from a generation of an alert of a user (or passenger) of the vehicle V of this prohibition of use of the electric motor machine MME and a recording of at least one fault code representative of an internal temperature gradient problem in the MME electric motor machine.

The user of the vehicle V can be alerted, for example, by means of a lit indicator light (for example on the dashboard or the charging plate which includes the CN charging connector) and/or a message displayed on at least one screen of the vehicle V (for example on the dashboard or a central instrument panel) or on the screen of a smart phone (or “smartphone”) of the user, and/or broadcast by at least one speaker of the vehicle V or this smartphone.

The recording of at least one fault code representative of an internal temperature gradient problem in the MME electric drive machine is intended to facilitate the search for the origin of a ban on the use of the MME electric drive machine by a technician from an after-sales service, and to allow this technician to inform the user of vehicle V of the origin of such a ban.

It will also be noted that step 10-40 can also include a sub-step 40 in which it is considered that a problem on the internal temperature of the electric motor machine MME previously detected is no longer present when the determined information ig becomes less than a third chosen threshold s3, less than or equal to the first chosen threshold s1, during a fourth chosen time interval it4. In this case, we (the DS monitoring device) re-authorizes the use of the MME electric driving machine (previously prohibited). Preferably, we also stop generating an (the DS monitoring device stops triggering the generation of a) alert for the user (when this additional action is planned).

It will be noted that when we implement the two conditions on the information ig and the internal temperature measurement mti, we (the monitoring device DS) re-authorizes the use of the electric motor machine MME when the information determined ig becomes lower than the third threshold s3 during a fourth time interval it4 chosen and the internal temperature measurement mti becomes lower than a fourth threshold s4 chosen during this fourth time interval it4.

For example, the third threshold s3 can be equal to the first threshold s1. But this is not obligatory. Thus, the third threshold s3 could be strictly lower than the first threshold s1.

Also for example, the fourth threshold s4 can be equal to the second threshold s2. But this is not obligatory. Thus, the fourth threshold s4 could be strictly lower than the second threshold s2.

Also for example, the fourth time interval it4 may be equal to the second time interval it2. But this is not obligatory. Thus, the fourth time interval it4 could be strictly greater than the second time interval it2.

It should also be noted that once monitoring has started it is preferable not to start determining the information ig after the very first time interval it1, and therefore to wait a little longer than it1. This makes it possible to stabilize the mti measurements and to provide sufficient successive mti measurements to determine a first piece of information ig. For example, this wait can be between 1.5*it1 and 2*it1.

Note also, as illustrated non-limitatively in the , that the CG management computer (or the dedicated computer of the DS monitoring device) can also include a mass memory MM1, in particular for the temporary storage of each internal temperature measurement mti and any intermediate data involved in all its calculations and treatments. Furthermore, this CG management computer (or the dedicated computer of the DS monitoring device) can also include an IE input interface for receiving at least the internal temperature measurements mti, to use them in calculations or processing , possibly after having shaped and/or demodulated and/or amplified them, in a manner known per se, by means of a digital signal processor PR2. In addition, this CG management computer (or the dedicated computer of the DS monitoring device) can also include an IS output interface, in particular to deliver orders temporarily prohibiting the use of the electric motor machine MME, or messages user alert, or messages containing a fault code.

It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1 is capable of implementing the monitoring method described above to monitor the periodic measurements mti of the internal temperature of the electric motor machine MME.

Claims (10)

Monitoring method for a vehicle (V) comprising an electric motor machine (MME) periodically subject to a measurement of an internal temperature, characterized in that it comprises a step (10-40) in which one determines periodically information representative of a gradient of said internal temperature measurements over a first chosen time interval, and when said information is greater than a first chosen threshold, the use of said electric motor machine (MME) is temporarily prohibited. Method according to claim 1, characterized in that in said step (10-40) the use of said electric motor machine (MME) is temporarily prohibited when said determined information is greater than said first threshold chosen during a second strictly greater time interval. said first time interval. Method according to claim 1 or 2, characterized in that in said step (10-40) the use of said electric motor machine (MME) is temporarily prohibited when in addition said internal temperature measurement is greater than a second chosen threshold . Method according to claim 3, characterized in that in said step (10-40) the use of said electric motor machine (MME) is temporarily prohibited when in addition said internal temperature measurement is greater than said second threshold chosen during a third chosen time interval. Method according to claim 3 or 4, characterized in that in said step (10-40) said second chosen threshold is between 175°C and 195°C. Method according to one of claims 1 to 5, characterized in that in said step (10-40), in the event of a temporary ban on the use of said electric motor machine (MME), ( V) at least one complementary action chosen from a generation of an alert from a user of said vehicle (V) of said prohibition of use of said electric motor machine (MME) and a recording of at least one fault code representative of 'an internal temperature gradient problem in said electric motor machine (MME). Method according to one of claims 1 to 6, characterized in that in said step (10-40) the use of said electric motor machine (MME) is re-authorized when said determined information becomes less than a third chosen threshold, less than or equal to said first chosen threshold, during a fourth chosen time interval. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the monitoring method according to one of claims 1 to 7 to monitor periodic measurements of an internal temperature of an electric motor machine (MME) of a vehicle (V). Monitoring device (DS) for a vehicle (V) comprising an electric motor machine (MME) periodically subject to a measurement of an internal temperature, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting of periodically determining information representative of a gradient of said internal temperature measurements over a first chosen time interval, and when said information is greater than a first chosen threshold to temporarily prohibit the use of said electric motor machine (MME). Vehicle (V) comprising an electric motor machine (MME) periodically subject to a measurement of an internal temperature, characterized in that it further comprises a monitoring device (DS) according to claim 9.